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/* $OpenBSD: compress.c,v 1.2 2006/04/05 01:38:55 ray Exp $ */
/*
* Copyright (c) 2005 Jean-Francois Brousseau <jfb@openbsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include "log.h"
#include "cvs.h"
#include "compress.h"
#define CVS_ZLIB_BUFSIZE 1024
struct cvs_zlib_ctx {
int z_level;
z_stream z_instrm;
z_stream z_destrm;
};
/*
* cvs_zlib_newctx()
*
* Allocate a new ZLIB context structure used for both inflation and deflation
* of data with compression level <level>, which must be between 0 and 9. A
* value of 0 means no compression, and 9 is the highest level of compression.
*/
CVSZCTX *
cvs_zlib_newctx(int level)
{
CVSZCTX *ctx;
if ((level < 0) || (level > 9))
fatal("invalid compression level %d (must be between 0 and 9)",
level);
ctx = xcalloc(1, sizeof(*ctx));
ctx->z_level = level;
ctx->z_instrm.zalloc = Z_NULL;
ctx->z_instrm.zfree = Z_NULL;
ctx->z_instrm.opaque = Z_NULL;
ctx->z_destrm.zalloc = Z_NULL;
ctx->z_destrm.zfree = Z_NULL;
ctx->z_destrm.opaque = Z_NULL;
if ((inflateInit(&(ctx->z_instrm)) != Z_OK) ||
(deflateInit(&(ctx->z_destrm), level) != Z_OK))
fatal("failed to initialize zlib streams");
return (ctx);
}
/*
* cvs_zlib_free()
*
* Free a ZLIB context previously allocated with cvs_zlib_newctx().
*/
void
cvs_zlib_free(CVSZCTX *ctx)
{
if (ctx != NULL) {
(void)inflateEnd(&(ctx->z_instrm));
(void)deflateEnd(&(ctx->z_destrm));
xfree(ctx);
}
}
/*
* cvs_zlib_inflate()
*
* Decompress the first <slen> bytes of <src> using the zlib context <ctx> and
* store the resulting data in <dst>.
* Returns the number of bytes inflated on success, or -1 on failure.
*/
int
cvs_zlib_inflate(CVSZCTX *ctx, BUF *dst, u_char *src, size_t slen)
{
int bytes, ret;
u_char buf[CVS_ZLIB_BUFSIZE];
bytes = 0;
cvs_buf_empty(dst);
inflateReset(&(ctx->z_instrm));
ctx->z_instrm.next_in = src;
ctx->z_instrm.avail_in = slen;
do {
ctx->z_instrm.next_out = buf;
ctx->z_instrm.avail_out = sizeof(buf);
ret = inflate(&(ctx->z_instrm), Z_FINISH);
if ((ret == Z_MEM_ERROR) || (ret == Z_BUF_ERROR) ||
(ret == Z_STREAM_ERROR) || (ret == Z_DATA_ERROR))
fatal("inflate error: %s", ctx->z_instrm.msg);
cvs_buf_append(dst, buf, ctx->z_instrm.avail_out);
bytes += sizeof(buf) - ctx->z_instrm.avail_out;
} while (ret != Z_STREAM_END);
return (bytes);
}
/*
* cvs_zlib_deflate()
*
* Compress the first <slen> bytes of <src> using the zlib context <ctx> and
* store the resulting data in <dst>.
* Returns the number of bytes deflated on success, or -1 on failure.
*/
int
cvs_zlib_deflate(CVSZCTX *ctx, BUF *dst, u_char *src, size_t slen)
{
int bytes, ret;
u_char buf[CVS_ZLIB_BUFSIZE];
bytes = 0;
cvs_buf_empty(dst);
deflateReset(&(ctx->z_destrm));
ctx->z_destrm.next_in = src;
ctx->z_destrm.avail_in = slen;
do {
ctx->z_destrm.next_out = buf;
ctx->z_destrm.avail_out = sizeof(buf);
ret = deflate(&(ctx->z_destrm), Z_FINISH);
if ((ret == Z_STREAM_ERROR) || (ret == Z_BUF_ERROR))
fatal("deflate error: %s", ctx->z_destrm.msg);
if (cvs_buf_append(dst, buf,
sizeof(buf) - ctx->z_destrm.avail_out) < 0)
return (-1);
bytes += sizeof(buf) - ctx->z_destrm.avail_out;
} while (ret != Z_STREAM_END);
return (bytes);
}
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